Rust on Alfa 147

I purchased a second hand 2001Y 147 1.6TS Lusso approx 8 months ago from
Dixons Motors in Leeds. This came with a 1 years Dixons warantee. However,
I have just noticed rust at the bottom the rear door near the wheel arch. I
took it into Alfa who told me this must be because the previous owner must
have had a scratch and has tried to cover it up himself. There is no
evidence of a touch up so if this is the case it must have been a complete
re-spray on the door. Very unlikely! They said this as there seems to be a
drip/run in the paint near the infected area on the rim of the wheel arch.
Personally i'm not convinced by this excuse. Apparently they have a
specialist who can measure the thickness of the paint on the car so they
can tell if it has been touched up or not. This has been arranged for next
month.

Anyway, I personally think my warranty should cover this. Does anyone else
agree? Has anyone else had a similar experience?

Thanks in advance for your time and help

Mark